The biochemical aspect of the research proposal is to investigate the biosynthesis and metabolism of protaglandins and thromaboxane in gingival tissues. Preliminary studies had shown the prostaglandin E2 levels are elevated in diseased human gingiva and may, therefore, participate in the pathogenesis of peridontal disease. Subcellular fractions of the gingival tissue obtained from patients with peridontal disease will be used for assays of the enzymes (phospholipase, PG synthetase and cyclooxygenase and thromboxane synthetase) which are intimately involved in the biosynthesis of prostaglandins and thromboxane. The endoperoxide intermediates PGG2 and PGH2 will be isolated and their biological activity evaluated. The mechanism for the formation of thromboxane A2 and hydroxy fatty acid will also be examined. In the study of prostaglandin metabolism, 14C or 3H labeled PG will be used as substrate, and the activities of the metabolic enzymes (15-OH-dehydrogenase, delta 13,14 reductase and PGE 9-detroreductase) will be measured. The sensitivity of the PGE 15 OH-dehydrogenase and PGE 9-ketroreductase to different vasoactive peptides and steroid hormaones will be given special attention. Further investigations of the release and ultimate fate of these vaoactive lipids will then be related to the possible physiological mechanism for the regulation of the inflammatory process and bone resorption in peridontal disease.